Modulated critical currents of spin-transfer torque-induced resistance changes in NiCu/Cu multilayered nanowires.

We present a novel method combining anodic aluminum oxide template synthesis and nanolithography to selectively deposit vertically patterned magnetic nanowires on a Si substrate. With this approach we fabricated three-dimensional nanowire-based spin valve devices without the need of complex etching processes or additional spacer coating. Through this method, we successfully obtained NiCu/Cu multilayered nanowire arrays with a controlled sequence along the long axis of the nanowires. Both magnetic switching and excitation phenomena driven by spin-polarized currents were clearly demonstrated in our NiCu/Cu multilayered nanowires. Moreover, the critical currents for switching and excitation were observed to be modulated in an oscillatory manner by the magnetic field in the nanowire-based devices. We present a toy model to qualitatively explain these observations.

Detection of DNA hybridization on a liposome surface using ultrasound velocimetry and turbidimetry methods.

19-mer oligonucleotides with oleylamine tethered at 3' and 5' terminal, respectively, were incorporated into unilamellar liposomes of dioleoylphosphatidylcholine (DOPC). Addition of complementary nucleotide resulted in hybridization with oligonucleotides located on different liposomes and caused liposome aggregation. Significant changes of sound velocimetry and turbidity were readily observed at 10 nM concentration of the complementary chain.